Fuel igniter gap setting device



Oct. 31, 1961 A. J. BATTEY ETAL 3,006,405

FUEL IGNITER GAP SETTING DEVICE Filed Sept. 28, 1959 f 6 I v-E x l7 s 1222/ g F/GJ v D/ A 7 L20 2 INVENTORS Iv A. .1. BATTEY GAP C. J. NOL/N ATTORNEY United States Patent 3,006,405 FUEL IGNITER GAP SETTING DEVICE Alexander J. Battey, Skaneateles, and Charles J. Nolin, Auburn, N.Y., assignors to Auburn Spark Plug Co., gncorporated, New York, N.Y., a corporation of New ork Filed Sept. 28, 1959, Ser. No. 842,818 11 Claims. (Cl. 158-48) This invention relates to igniters for gasoline, gas and oil burning equipment and consists more particularly in new and useful improvements in a method and device for accurately setting the gap between the center electrode of the igniter and a ground terminal located in the combustion chamber or a part of the chamber with which the igniter is used.

In fuel burners of the type in question, igniters are usually made without a ground electrode, ignition usually being eflEected by the spark jumping from the center electrode of the igniter to some part of the case within the combustion chamber or adjacent thereto. Designers and manufacturers of this burning equipment have apparently given little thought to the problem of insuring a proper gap setting within the combustion chamber.

Ordinarily, it is necessary to remove the cover of the combustion chamber and bend the center electrode to obtain the proper gap which not only consumes considerable time but is expensive. Furthermore, the bending of the center electrode often causes a fracture of the insulator through which the center electrode passes which, of course, destroys the effectiveness of the insulator and igniter.

An object of the present invention is to provide a method and device for insuring a proper gap between the center electrode and ground terminal in the combustion chamber without the necessity of removing the cover or any portion of the combustion chamber or igniter, or

bending the center electrode of the igniter.

Another object of the invention is to provide a consumable spacing element associated with the firing end of the center electrode for defining the proper gap between the center electrode and an adjacent ground terminal.

A further object of the. invention is to provide an igniter assembly for fuel burning equipment including a self-consumable spacing element adapted to define the gap "between the center electrodeand a ground terminal in the combustion chamber and which upon ignition in the combustion chamber, is completely destroyed to provide the proper gap setting.

With the above and other objects in view which will appear as the description proceeds, the invention consists in the novel features herein set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designate similar parts throughout the several views:

FIG. 1 is .a diagrammatic sectional view of a fuel humor with the igniter of the present invention installed and shown partially in section with the self-consumable spacing element in position;

FIG. 2 is a similar view showing the consumable spacing element of the invention in the course of being destroyed;

FIG. 3 is an enlarged fragmentary detail of the flanged upper end of the center electrode; and

ice

FIG. 4 is a modified form of consumable spacing element.

In the drawings, 5 represents the cover of a conventional gasoline heater having a hollow dome-like portion 6 which is diagonally drilled and threaded as at 7 to receive the threaded end of an igniter, generally indicated at 8. The igniter consists of a steel shell 9, the lower end of which is threaded as at 10 to engage the. threads 7 in the dome 6. An insulator 11 fits snugly within the shell 9 and projects longitudinally from the upper and lower ends thereof, its lower end extending into the combustion chamber 12, closed by the cover 5, and its upper end'forming an insulator head 13 which may be tapered or ribbed.

A center electrode 14 is adapted to fit in a complementary bore in the, insulator 11, its upper end being slightly enlarged and threaded as at 15, to engage complementary threads 16 in an enlarged portion of the bore at the upper end of the insulator head 13. The center electrode 14 is of sufiicient length to project downwardly into the combustion chamber 12 beneath the cover 5, with its lower extremity 17 terminating adjacent a ground terminal formed by any convenient part of the case or cover within the combustion chamber. In the form of the invention shown in the drawing, a projection 18 formed on the underside of the cover 5, serves as the ground terminal for the center electrode 14.

The threaded end 15 of the center electrode projects outwardly beyond the insulator head 13 and its outer extremity may be reduced as at 15a to receive a terminal nut (not shown) for securing an electrical conductor in place on the electrode. A flange or shoulder 19 is pro- .vided intermediate the threads 15 and 15a for abutment with the adjacent end of the insulator head 13, to maintain the center electrode 14 in place within the. insulator 11, upon engagement of the complementary threads 15 and 16 of the center electrode and insulator head respectively. The center electrode may or may not be permanently cemented within the center bore of the insulator.

In either event, with the center'electrode in fixed relation to the insulator, when the igniter Sis screwed into the threaded opening 7 in the cover 5, the center electrode 14 moves bodily therewith in fixed relationship.

.-A spacing capsule 26 in the form of an openecnded cylinder composed of any suitable consumable insulating material such as Celluloid or the like, isadapted to fit on the inner extremity 17 of the center electrode 14. This capsule is designed to project a predetermined distance beyond the end of the center electrode, to define the desired spacing of the end 17 of the electrode from-the adjacent face of the ground terminal portion 18 of the combustion chamber, when the igniter 8 isinserted in the cover 5 to the extent that the capsule 20 contacts the ground terminal '13 as shown in FIG. 1. The-hollow interior of the capsule 20 forms a small chamber '21 which is filled with an explosive or other ignitablematerial, and the end wall of the capsule is provided with a small vent or hole 22 through which a spark can jump to. thetground terminal 18 when the center electrode 14 is energized.

In the installation and use of this invention, the igniter 8 is screwed into the threaded opening 7 of the heater cover Suntil the capsule 20 on the end of the center electrode 14 contacts the abutment or ground terminal 18 in the combustion chamber 12. A conventional jam nut 23 on the threaded portion 10 of the igniter shell 9, is then tightened to the face of the cover- 5 which secures the igniter firmly in place. The high tension lead of the ignition system (not shown) is then connected to the threaded end 15a of the center electrode, and when the ignition is turned on, energizing the center electrode 14, a spark jumps through the hole 22 in the capsule 20, from the end 17 of the center electrode to ground 18. This spark, passing through the explosive in chamber 21, ignites the same and as a result, the capsule is completely destroyed, leaving a measured gap between the end 17 of the center electrode and the ground terminal 18.

The enlarged threaded portion 15, 15a of the center electrode may be formed integrally with the electrode, or if desired, the enlarged threaded end may be welded on the end of the electrode as shown in FIG. 3.

In the modified form of the invention shown in FIG. 4, instead of applying the consumable spacing element directly to the firing end of the electrode 14, it is attached to the surface of the ground terminal 18 between the latter and the center electrode 14. This modified spacing element comprises a hollow body 20a, formed of Celluloid or other material suitable for the desired purpose, the central portion of said body being extended throughthe hollow area to form a stud Zfib adapted to fit within a complementary opening 18a in the ground terminal 18, whereby the body Zita is retained in place against the face of the ground terminal. The hollow body 20a defines a chamber 21a adapted to receive a quantity of explosive material and the outer wall of the body 213:: is provided with suitable ports or openings 22a through which a spark can jump to the ground terminal 18 when the center electrode 14 is energized.

The operation of this modified form of the invention is essentially the same as that just described. Upon energizing the center electrode 14, a spark jumps from the end thereof through the openings 22a to the ground terminal 18, simultaneously igniting the explosive in chamber 21a and destroying the spacing element 26a.

Upon the disappearance of the spacing element 20a, the

proper gap is provided between the center electrode 14 and the ground terminal 18.

It may be stated also that while we have described the capsule as being formed of Celluloid, many different insulating materials which will burn or be destroyed either through ignition with the electric spark or a combination of the spark and ignited fuel, may be employed.

It will thus be seen that we have provided a very simple means for accurately obtaining a definite setting of the gap for an igniter, while the latter is installed in the combustion chamber of a fuel burner, without requiring the removal of the combustion chamber cover .or any other part of the apparatus.

without departing from the spirit of the invention as set forth in the following claims.

We claim:

1. A method of setting the gap between the center electrode of a fuel igniter and a fixed ground terminal in the combustion chamber of a fuel burner or the like, comprising interposing between the firing end of said electrode and said ground terminal, in contact with both, a spark penetrable body of consumable electrical insulating material including an explosive substance, and potentializing said center electrode to cause a spark to jump through said body, whereby the latter is destroyed, leaving a fixed gap between the center electrode and ground terminal. a

2. A method of setting the gap between the center electrode of a fuel igniter and a fixed ground terminal in the combustion chamber of a fuel burner or the like, comprising applying to the firing end of said center electrode, a' spark penetrable body of consumable electrical 4 V insulating material including an explosive substance, which projects beyond said firing end a predetermined distance defining the desired gap setting, projecting said igniter into said combustion chamber until said body abuts said ground terminal, and potentializing the center electrode to cause a spark to jump from said center electrode to said ground terminal, through said body, whereby the latter is destroyed, leaving a fixed gap between the center electrode and ground terminal.

3. A method for insuring the correct gap for igniters within a closed space having a ground terminal, comprising interposing between the firing end of said electrode and said ground terminal, in contact with both, a spark penetrable body of consumable electrical insulating material including an explosive substance, and potentializing the center electrode to cause a spark to jump through said body, whereby the latter is destroyed, leaving a fixed gap between the center electrode and ground terminal.

4. In a fuel burner having a fixed ground terminal'in the combustion chamber thereof, an igniter comprising a center electrode adapted to be projected into said combustion chamber to a point adjacent said ground terminal, and a spark penetrable spacing device of consumable electrical insulating material including an explosive substance, carried on the firing end of said electrode and projecting longitudinally beyond said firing end a distance defining a predetermined gap setting, and in line for abutment with said ground terminal, whereby, when said device abuts said ground terminal, the firing end of said electrode is spaced therefrom the distance of said predetermined gap setting, and when a spark penetrates said device and combustion occurs in said chamber, said device is destroyed, leaving a predetermined gap.

5. In a fuel burner having a fixed ground terminal in the combustion chamber thereof, an igniter comprising an igniter shell, an insulator extending therethrough, a center electrode projecting longitudinally beyond the inner extremity of said insulator, said shell being adapted for insertion in said burner with the firing end of said center electrode projecting into said combustion chamber to a point adjacent said ground terminal, a spark penetrable spacing device of consumable electrical insulating material including an explosive substance, carried on the firing end of said electrode and projecting longitudinally, a distance defining a predetermined gap setting, and in line for abutment with said ground electrode, and means for locking said igniter in place in said burner with said device in contact with said ground terminal, whereby the firing end of said electrode is spaced from said ground terminal the distance of said predetermined gap setting and when a spark penetrates said device and combustion occurs in said chamber, said device is destroyed, leaving a predetermined gap.

6. Apparatus as claimed in claim 5,.wherein said spacing device comprises an open ended cylinder adapted to be mounted on the firing end of said center electrode.

7. Apparatus as claimed in claim 5, wherein said spacing device comprises a cylinder adapted to be secured on the firing end of said center electrode, and having a chamber therein containing said explosive substance.

8. Apparatus as claimed in claim 5, wherein the projecting end of said device adjacent said ground terminal is provided with a small opening through which a spark is adapted to jump from the firing end of said electrode to said ground terminal to ignite said consumable material.

9. In a fuel burner having a fixed ground terminal in the combustion chamber thereof, an igniter comprising a center electrode adapted to be projected into said combustion chamber to a point adjacent said groundterminal, and a spark penetrable spacing device of consumable electrical insulating material including an explosive substance, interposed between and in contact with the firing end of said electrode and the adjacent face of said ground terminal, the thickness of said spacing device defining a spacing device comprises a hollow vented body containpredetermined gap setting, whereby, when combustion ing said explosive substance. occurs in said chamber, said device is destroyed, leaving a predetermined gap References Cited in the file of this patent 10. Apparatus as claimed in claim 9, wherein said 6 UNITED STA PATENTS spacing device is attached to a face of said ground ter- 2 413 731 Samuel Jam 7 1947 minal in line for abutment by the firing end of said cen- 2:45O:197 Ishler Sept. 1948 electmde- 2,460,022 McCarthy et a1. Jan. 25, 1949 11. Apparatus as claimed 1n claim 10, Wherem s 21334363 DLuzansky Apr, 7 959 

